<?php
plugin_add_hook('PRE_TEMPLATE',  'plugin_x_capture_output');
plugin_add_hook('POST_TEMPLATE', 'plugin_x_process_output');

function plugin_x_capture_output($t) {
	ob_start();
	return $t;
}

function plugin_x_process_output() {
	$template_output = ob_get_contents();
	ob_end_clean();
        // Modify output, add headers, footers, go mad...
	echo $template_output;
}
?>